GMC GMT 610, Manual

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G/H Van (GMT 610) 2005
G/H V
AN
(
GMT 610
)
4
P
AGE
(Section 1 — continued from previous page)
Air Conditioning
For additional information refer to Engine - Section 6.
NOTE: Air conditioning systems using R-134A refrigerant are equipped with metric fittings to prevent interchange with R-12 refrigerant
components. Do not interchange R-134A components, refrigerant oil or service equipment with R-12 components, refrigerant oil or
service equipment.
Rear Air Conditioning
The A/C and heater lines are usually routed between the vehicle floor and the exhaust system heat shields. The electrical connectors for the
rear HVAC are usually routed on the inside right rear pillar and it also has a switch on the front dash to control the rear air.
NOTE: It is imperative that the design of the HVAC lines and materials selected by the Conversion Companies, upfitter (or HVAC supplier)
provide mechanical attachments to the vehicle to protect against abrasion, engine roll, and vibration. The lines must also be
insulated to protect against engine or exhaust system heat. Please be aware that an improperly installed HVAC system by the SVM
may damage OEM and/or van conversion system components.
This unit may be equipped with A/C quick-connect fittings on the liquid tube (high pressure) and the suction (low pressure) return tube.
These fittings are designed to accept matching Aeroquip connecting fittings attached to pre-charged lines. This allows a one time only
connection to the O.E.M. charged A/C system without having to discharge, evacuate and recharge for the connection of a rear A/C system.
These quick connects must be used for warranty coverage of the A/C system.
A modification to the A/C system which causes the A/C plumbing lines to increase in length (such as the addition of a rear after-market
evaporator and blower assembly) will necessitate the following changes:
• Lubrication – PAG refrigerant oil must be added to rear system to provide lubrication for compressor. Refer to the G Van Service
Manual for specifications.
• Refrigerant – Add R-134A refrigerant to system based on sizing of new tubes, hoses and evaporator. Contact your A/C supplier for
recommended charge.
• Label – Revise/modify GM charge label (located on the front face of evaporator) from factory recommended charge for a front
system only to body builder’s new recommended dual system per SAE J639. This is important for servicing the A/C system so
that the technician knows the correct amount to add to the modified system.
• Heater/Defroster – No modifications should be made to the heater/defroster system or coolant supply which could affect
compliance to FMVSS 103.